Pisano is described as being 5'6'' tall, of slim build and aged around 35.

He may have grown a beard or be disguising himself in other ways since the photograph, featured above, was taken in early 2012.

Although originally from South Africa, he may have changed his accent, and also lived in New Zealand.

Detective Chief Inspector Nick May, who is leading the investigation known as Operation Journal, said: ‘We are still unclear as to when exactly Polding died and our enquiries have shown that Polding was friends with Pisano.

‘We think he may have information about Polding's last movements, however we have been unable to find him so far.’

He added that Pisano has links to Brighton, Croydon, Crouch End in north London and Southampton where he was last seen on 28 July at Marlands shopping centre.

However, he could have since moved to other areas of the country.

‘He could be introducing himself under a number of different names and I would urge people to look at his photograph and contact police if they have seen him recently,’ DCI May said.

‘Any information, no matter how small, could be significant to our enquiry.

‘I would also like to appeal for Pisano to get in contact with Sussex Police directly.’

If you have any information on Pisano and his whereabouts, call Sussex Police on +44 101 quoting Operation Journal or Crimestoppers anonymously on +44(0)800 555 111.

Polding's death was initially treated as unexplained but following a post-mortem on 21 July, a murder investigation was launched. The post-mortem showed that Polding suffered a number of injuries, which led to his death.

The victim was an openly gay man but police are not treating his death as a hate crime.

A 28-year-old man from North London was arrested on suspicion of murder on 22 July and has been bailed until 23 August, pending further enquiries.